Mk3 convertible revisit after 12 years in a garage

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Re: Mk3 convertible revisit after 12 years in a garage

Postby Stuart » Wed May 21, 2025 7:43 am

Interesing to see the differences on the K-series arms, I've never seen anyone online ever do a comparison and was wrongly under the impression it was only the axle thread and slot that were different.
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Re: Mk3 convertible revisit after 12 years in a garage

Postby manifold » Wed May 21, 2025 5:10 pm

Yes it was a surprise to me too Stuart. The actual knuckle cup is bigger on the K series radius arms. Someone mentioned to me recently that the cost is massively more expensive now for replacement knuckles for the later K series arms due to them being rarer. Apparently the earlier ones might be more compatible with the ones from minis.
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Re: Mk3 convertible revisit after 12 years in a garage

Postby manifold » Wed May 21, 2025 5:20 pm

Another comparison for today. :).

I bought a few radius arm repair kits recently. This topic may have already been covered. Sorry if it has. I noticed that the radius arm repair kits for metros are getting rather a bit rarer now on ebay. So bear that in mind if you have a Mk3 or Mk4 Midas.

For interest I bought a mini radius arm repair kit to see what the similarities are. I did this knowing full well that the inner bush on a mini is scintered/ phosphor bronze which has to be reamed - but what I was interested in knowing is what the radius arm dust seals are like and what the outer needle roller bearings are like in comparison to metro ones.

It turns out that the mini needle roller bearings are exactly the same, along with the earlier (see above reference to the dust seals) are the same too. What is different though is the overall length of the radius arm shaft. Its a longer shaft on the mini (which I kind of knew anyway).

The nuts and threads are different too. Useful to know if your radius arm shaft is still in good working order but the needle roller bearings are worn out and your needing to get it back on the road, go for an MOT (if it still applies) or for whatever other reason.

I recon you can use the mini grease tube on the metro shaft too. Its actually longer... which is better at getting the grease to the opposite end which is one of the bug bears of this design. Especially on radius arms which are hollow.....which would need filling up with a lot of grease (a trick mini owners do).

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Re: Mk3 convertible revisit after 12 years in a garage

Postby manifold » Fri Jun 06, 2025 10:59 am

Another comparison. This time regarding metro A series and K series front subframe rear mountings.

I bought a set of stainless ones from a K series to see how they compare to the A series ones. Note the stainless K series one is an aftermarket product but it will be dimensionally correct.

As you may well know, the rubber bushes on these tends to perish after a while and is an MOT failure.

Note the size different between the 2. The A series is the bigger one.

The A series also has a longer bolt and the thread is different to the K series, albeit its the same diameter bolt.

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Re: Mk3 convertible revisit after 12 years in a garage

Postby manifold » Fri Jun 06, 2025 11:04 am

Another point to note is the fixings positioning.

It is different between the two mounts.

The rear holes align with the positioning hole but the front ones are a few mm closer together.

The difference in overall length is basically the cotton reel shape to the front of the mount on the A series.

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Re: Mk3 convertible revisit after 12 years in a garage

Postby manifold » Fri Jun 06, 2025 11:08 am

Big thanks to both Victor Craig from Scotland and Alan Donowho from Newcastle for sorting me out a new old stock rear metro subframe and a set of extended rear stub axles. I can now start to put the Convertible back on 4 wheels again in the coming weeks. I must say those extended rear stub axles are a nice piece of machining. Nice radius in the corners. I am well happy.

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Re: Mk3 convertible revisit after 12 years in a garage

Postby manifold » Fri Sep 26, 2025 10:46 am

After a small break due to weddings and other distractions getting back under way with the back end of my convertible.

Stripped off the old subframe and painted up with a couple of extra coats of paint a NOS rear subframe thanks to Victor.

Also sources a couple of cheap NOS mk2 metro radius arms which I will paint up with some smooth enamel this weekend and get those shiney rear stubs pressed in. Honestly cant wait to see my convertible rolling on the floor again after such a long time.

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Re: Mk3 convertible revisit after 12 years in a garage

Postby manifold » Fri Sep 26, 2025 10:47 am

Looks like I need a few new exhaust bobbins. The current ones have rotted to oblivion.
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Re: Mk3 convertible revisit after 12 years in a garage

Postby manifold » Fri Sep 26, 2025 10:56 am

I wIll be waxolying this rear subframe too so treated myself to a waxoyl applicator attachment for the compressor . The rear subframes tend to rot from the inside out.
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Re: Mk3 convertible revisit after 12 years in a garage

Postby manifold » Sat Sep 27, 2025 1:12 pm

Spent some time today sorting out the replacement stub axles for a pair of NOS mk2 metro radius arms I managed to source.

Some pics here of how to fit them using a 10 ton press I had knocking about for this kind of thing. Usually pressing bearings. Thanks to Alan D for supply the extended stub axles pair. Just need a pair for my Midas Coupe (plus a spare set) :) . Threads are handed for the wheel bearing so make sure you put them on the right way round with the correct thread orientation first. Fortunately I have already changed the bottom rubber bushes on my shocks to the wider ID so one less job to do.


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